Clean

It doesn’t catch every spec, but it does a fine job of keeping dust to a minimum.

Control

Because the Bosch GEX 125-1 AE comes with variable speed, you have control over sanding velocity.

This is a brilliant feature, because higher speeds coupled with uneven surfaces cause tool-walk. This is when the tool (in this case, a sander) bucks your direction in favour of its own course. This could cause scratches, which require more sanding.

Replaceable sanding plate

Your sanding plate worn through from too much sanding? Don’t chuck your machine into the bin.

Simply change out the old sanding plate for a new one and you’re good to go.

How to use

How to sand

Don’t apply too much pressure when you sand with the Bosch ROS. Rely on its weight to do most of the work. Your job is to guide the machine to where you want it to sand.

You needn’t worry about sanding direction. The Bosch GEX 125-1 AE is direction agnostic. It doesn’t leave marks, irrespective of which direction you sand your surface in. This is not the case with a belt sander, orbital sander or sanding disc, all of which leave scratch marks if you don’t sand with the grain.

If your surface is in a bad state, start with a rough grit sanding disc. I use a 40 grit on some jobs. It might be too heavy for the average sanding job, so perhaps start with an 80 grit. Work your way up from there. (Remember, the higher the grit number, the smoother the sanding paper.) I use 40, 60, 80, 120, 150, 220, 300 and 400 grit sanding paper. At the 400 mark the wood starts to reach a “smooth-as-butter” feel. If you wish, work it up to 600, perhaps beyond.

If your Bosch sander runs around on the job, drop the speed, or ramp it up, until you’re in control.

Sanding disc info

The Bosch ROS’ sanding plate is one half of a hook and loop system. It has eight holes. Let’s take a closer look.

Velcro

The GEX 125-1 AE uses a Velcro (or hook and loop) system for gripping sanding discs.

This is an excellent system, because it allows for rapid change of sanding discs. Change sanding discs in seconds and get the job done in no time.

Sanding tests

The Bosch GEX 125-1 AE excels at sanding wood. I tackled a number of projects with it, apart from the skimboards (for which I bought it).

I sanded 18mm shutterply for a corridor cupboard, for one.

I went from 40 grit through to 400 grit, giving the wood a finish so smooth it’ll make Kenny G jealous.

The left is unsanded, the right finished with the random orbit sander.

I sanded one of the first skimboards I made, to re-coat it. This didn’t work well, the reason being that the board was coated with a few coats of primer and a number of top coats. It clogged up the sanding discs. In future I’ll use a chemical paint stripper or heat gun to remove thick paint.

However, once the paint was off, getting the board smooth took only a few minutes.

Final thoughts

The Bosch GEX 125-1 AE (the 120V version is coded ROS20VSC) random orbit sander is an excellent tool for removing material and finishing wood.

It’s safe. A belt sander is fantastic for fast material removal. The problem is, it’ll remove your skin in no time too. It’s not a toy, especially if you’re not strong enough to handle it. The Bosch random orbit sander is much safer than a belt sander. I placed my hand on the sanding disc while it was running with a 40 grit disc, and it didn’t harm me.

It’s versatile. Although it doesn’t remove material as quickly as a belt sander, it’s much quicker than an orbital sander or a sanding block. It works on level surfaces, and I had no trouble shaping round corners.

It’s quick. Because the GEX’s sanding discs attach to the sander via Velcro (hook and loop fastening), you speed through different grits quicker than a Mustang racing a little old lady with a walking stick.

It’s easy. The discs are easy to remove. Also, you need not apply heavy pressure for it to work well. If you want to remove more material, faster, use a coarser grit. But don’t press too hard. Guide the tool and let it do the work for you. A normal orbital sander must be used in the direction of the grain. The Bosch random orbit sander is direction agnostic, meaning you can sand in any direction across your wooden project.

It gives a great finish. I needed a machine to handle rough and finish sanding. A beautiful, smooth finish is crucial (especially for my skimboards and my wife’s cupboards). The Bosch ROS gives me that.